The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A solid-state disk (SSD) is a data storage device that uses solid-state memory to store persistent data. Unlike flash-based memory cards, SSDs usually emulate hard disk drives (HDDs). SSDs using static random access memory (SRAM) or dynamic RAM (DRAM) instead of flash memory are often called RAM-drives, which require power to be applied to maintain the memory. NAND-based SSDs retain memory states when power is not applied.
The term “Solid State” in SSD refers to the use of semiconductor devices rather than electromechanical devices such as HDDs comprising motors and spinning disks. With no moving parts, SSDs are less fragile than HDDs and therefore also silent (unless a cooling fan is used). Since there are no mechanical delays, SSDs tend to have relatively low access times and latency. SSDs also tend to dissipate less power than HDDs. SSDs are being used more frequently in laptop computers. However, more significant use of the SSDs has been limited by their substantially higher storage cost per memory unit than the HDDs.